It is well known to use catalyst burners as a source of flameless and cordless heat in heat producing devices such as curling irons, soldering irons and the like. Catalytic burners include a catalytic material which oxidizes gaseous fuels, such as butane or propane, in the presence of air to produce the desired heat in such devices. In normal operation, fuel is discharged from a self-contained source of liquefied fuel through a nozzle, which converts the liquefied fuel to gas, mixed with air or other source of oxygen and delivered to a catalytic combustion chamber in which the catalytic burner is located.
The temperature to which the catalyst must be heated to initiate and sustain catalytic oxidation depends on the oxidation reaction itself and the activity of the catalyst. Some reactions can be initiated without any external heating at all. For example, the oxidation of methanol can be initiated at ambient or below ambient temperatures simply by exposing an active catalyst to mixtures of methanol and air. However, the oxidation of other fuels, such as butane and propane, require the temperature of the catalyst to be raised to a higher temperature, called the light-off temperature, before the oxidation reaction will occur. To that end, various methods, including frictional and electrical heating, have been developed to pre-heat the burner to the light-off temperature. A common method is to cause an explosion of a mixture of the combustible gas and oxygen (air) in or near the catalytic combustion chamber. In some cases, the heat produced by the explosion is sufficient to initiate the catalytic reaction. In other instances, the quantity of heat developed by explosion is insufficient, resulting in unsatisfactory operation of the device.
Conditions suitable for normal catalytic reactions are often less than ideal for initiating the reaction. A fully heated burner does not require particularly high gas flow rates or gas flow to impinge directly on the burner. The natural processes of convection and conduction are sufficient to direct the flow to the burner. While it is desirable to initiate an explosion within the combustion chamber, it is usually not physically possible to do so. Thus, the explosion must be initiated at a relatively remote location which results in less efficient heating and, frequently, less than satisfactory operation. Common deficiencies of known catalytic burners are lack of reliability in quickly reaching light-off temperature and incomplete oxidation during startup, resulting in unburned gases leaving the combustion chamber of the burner. In addition to these difficulties, known catalytic burners of the aforementioned type tend to be difficult to manufacture and assemble, physically unstable in the sense that they have a tendency to deform or break down, and may be subject to relatively low maximum operating temperatures.